1. Field of the Invention
The present invention relates to a system for feeding bottle-tops to a bottle closing machine, in particular for feeding caps to a capping machine, comprising an accumulation device located on a cap feeding pathway.
The present invention was developed in particular in view of its application to automatic plants for forming plastic bottles, filling and capping the bottles using plastic caps.
In plants of this type an accumulation device for the caps is normally provided for on the cap feeding pathway. The accumulation device has a minimum capacity such as to ensure that all containers present in the bottle forming, filling and capping stations can be capped even should the supply of caps be temporarily interrupted.
2. Description of the Related Art
The document EP-B1-0993417 describes a plant for filling and capping bottles provided with a mobile buffer stock device for the caps capable of moving the caps at a predetermined rate along a feeding pathway. The mobile buffer stock device described in that document comprises an inner drum that rotates around a vertical axis provided around its periphery with a plurality of housings that engage respective caps and an external helicoidal runway along which the caps are made to advance at a predetermined rate.
In the solution described in document EP-B1-0993417, the caps advance in a continuous fashion along the feeding route at a rate and an instantaneous velocity that depends on the work rhythm of the capping machine, so that the accumulation device must be designed and produced for a specific capping machine and cannot be used with capping machines having different characteristics. In the known solution, the caps must fill each housing of the accumulation device since any discontinuities would cause operating problems, such as for example the failure to close all containers. A further drawback of the known solution consists in the fact that each cap must cover the entire helicoidal or spiral pathway of the accumulation device, which entails a high risk that the accumulation device produces dust due to abrasion of the caps, and causes unnecessary stress on the caps.